Effect of drying methods on essential oil content and composition of wormwood (Artemisia absinthium L.)

The aerial parts of wormwood (Artemisia absinthium L.) were harvested in full blooming stage in September 2005 from an area between Deylaman and Asiabar villages, around the Siahkal city in Gilan province in north of Iran. In order to complete drying, a sample of aerial parts was placed at shade (room temperature) for several days and a sample placed in ventilated oven at 35^oC temperature for 24h. The aerial parts essential oil was extracted by hydrodistillation in a Clevenger apparatus and analyzed by GC/MS. Results showed that essential oil yields in shade condition and oven condition were 1.3 and 1.1 percent respectively. Also number of chemical components of the essential oil in shade drying and oven drying methods were 28 and 33 components respectively, which were mostly monoterpenes. β- pinene and β- thujone were main components of the both drying methods, which their contents in shade drying and oven drying methods were (23.8 and 18.6%) and (18.7 and 27.9%) respectively. Hydrocarbon monoterpenes content in shade drying method were higher than the other method but in case of oxygenated monoterpenes vice versa. There was not significant difference with respect to sesquiterpenes content between the drying methods. The results proved that chemo type of the studied wormwood essential oil was specific and different from other wormwood essential oil chemotypes, which have been reported.